feat: record line offset in block state

Author: galaxian85

lib/rules_block/blockquote.js

@@ -272,15 +272,27 @@ module.exports = function blockquote(state, startLine, endLine, silent) {
   state.parentType = oldParentType;
   lines[1] = state.line;
 
+  let totalLineOffset = 0;
   // Restore original tShift; this might not be necessary since the parser
   // has already been here, but just to make sure we can do that.
   for (i = 0; i < oldTShift.length; i++) {
-    state.bMarks[i + startLine] = oldBMarks[i];
-    state.tShift[i + startLine] = oldTShift[i];
-    state.sCount[i + startLine] = oldSCount[i];
-    state.bsCount[i + startLine] = oldBSCount[i];
+    const lineNumber = i + startLine;
+    if (state.lineOffsets[lineNumber] === null) {
+      state.lineOffsets[lineNumber] = totalLineOffset;
+      totalLineOffset += calcLineOffset(state, lineNumber);
+    }
+
+    state.bMarks[lineNumber] = oldBMarks[i];
+    state.tShift[lineNumber] = oldTShift[i];
+    state.sCount[lineNumber] = oldSCount[i];
+    state.bsCount[lineNumber] = oldBSCount[i];
   }
   state.blkIndent = oldIndent;
 
   return true;
 };
+
+function calcLineOffset (state, lineNumber) {
+  const previousLineEnd = state.eMarks[lineNumber - 1] + 1 || 0;
+  return state.bMarks[lineNumber] - previousLineEnd;
+}

lib/rules_block/state_block.js

@@ -31,6 +31,7 @@ function StateBlock(src, md, env, tokens) {
   this.eMarks = [];  // line end offsets for fast jumps
   this.tShift = [];  // offsets of the first non-space characters (tabs not expanded)
   this.sCount = [];  // indents for each line (tabs expanded)
+  this.lineOffsets = [];
 
   // An amount of virtual spaces (tabs expanded) between beginning
   // of each line (bMarks) and real beginning of that line.
@@ -92,6 +93,7 @@ function StateBlock(src, md, env, tokens) {
       this.tShift.push(indent);
       this.sCount.push(offset);
       this.bsCount.push(0);
+      this.lineOffsets.push(null);
 
       indent_found = false;
       indent = 0;
@@ -106,6 +108,7 @@ function StateBlock(src, md, env, tokens) {
   this.tShift.push(0);
   this.sCount.push(0);
   this.bsCount.push(0);
+  this.lineOffsets.push(null);
 
   this.lineMax = this.bMarks.length - 1; // don't count last fake line
 }